Dowel concrete joint



Patented July 7, 1925.

UNITED isT r s PATENT o' mE...,

EDWARD a. mm or nor am, vrnema.

DOWEL conc'nnrra mm.

Application and June af 1924. Serial no. 117,515.

To, all whom it may concern:

Be it known that I, EDWARD A. MARYE, a citizen of the United States, residing at Bon Air, in the county of Chesterfield and State of Virginia, have invented certain new and useful Improvements in Dowel Concrete Joints, of which the following is a specification.

This invention relates to concrete struc- The general mode of applying dowel rods in constructions of the kind referred to is to embed portions of the rods in a section of the structure with a portion, generally one-half, of the rods projecting therefrom, and, when the material of the first section has sufliciently set, the rods are withdrawn a short distance for the purpose of leaving chambers adjacent to the inner ends of the rods in which such ends may move when they or slabs in which they are contained, expand or contract when affected by chan es in climatic conditions. method is correct, but in practice it is by nomeans reliable. are withdrawn the apertures formed are more or less filled in by the falling into them of the material of the structure. The-,most frequent difiiculty encountered, however, is the failure on the part of workmen to withdraw the rods, and the latter: being embedded at their inner ends, their positions cannot accurately be ascertained, particularly after the composition" in which they are placed becomes set. Besides, workmen necessarily remain idle until the material sets sufficiently to allow withdrawal of the rods with the assurance that an open space will be formed adjacent to their inner ends.

The object of the present invention is to provide a dowel rod provided with means of such form that it may rapidly be put into position for use without especial care, and that the facility for expansion or contraction of the rod'or slabs in which it is conpredetermined Theoretically t is Frequently when the rods.

tained shall be insured under all conditions. A further object is to provide a dowel rod for the specified purpose which can be placed in sition for use without requiring partial wit drawal to form a chamber into which the rod may project under ex ansion, thus allowing of the construction 0 a succeeding adjacent section before the first has entirely set or completely hardened, and-thereby to efl'ect material saving in time in the work.

Having the above and other objects in view, the invention consists of a dowel rod for the general purpose referred to havin the novel generic and specificfeatures 0 construction and arrangement of parts, sub stantlally as hereinafter described and claimed. Y The'preferred form o f the dowel rod is illustrated in the accompanying drawing, in which: X

Figure 1 is a longitudinal sectional view of the rod;

Figure 2 is a view of the rod shown in position for use, and

Figure 3is 'a face view of a metal abutiment adapted for use in connection with the dowel rod, for instance, in the formation of roadbeds.

In this drawing 1 represents a rod, preferably of iron, circular in cross section, and

of any diameter suitable for use in the position in which it is to be placed. One end of the rod projects into a hollow cylindrical end piece'or cap 2, the opening in which is of a diameter and length to receive the end), of the rod and permit it free slidinginovement when the rod or slabs in which it is contained, are lengthened or shortened by reason of being. heated or cooled. One end of the cap or end piece is closed, and rojecting from the outer face of the cap 15 a projection of such form that when embedded in concrete or the like the cap will be held against lateral movement. The projection may, as herein shown, be in the form of a flange 3 extending outwardly aroundi the closed end of the cap or end piece.

The cap or end piece has extending through A its body an opening intwhich is placed a pin 4. The end of the pin projects into the I interior of the cap or end piece at a point removed from the closed end of the cap, and

the cap is determined. The pm is preferably oflead or other soft material, allow-' llll ing of its bein sheared by the end of the rod when the atter, after being placed in positionto abut against the pin, is lengthened by expansion of itself and of slabs in .which it is contained.

In placing the rods, made as described in place for use, they are first coated with some substance which will adhere to them and form alubricant to facilitate. their lengthening or shortening under changes in climatic conditions. For this purpose heavy oil, tar, tar paper, or a similar substance may be employed. The caps or end pieces arethen applied to the rods with the ends of the latter bearing on the pins, and the rods are passed through the openings 5 in the metal abutment 6 and caused to project beyond the outer face of-the abutment which is placed in position to give form to the end of a section of road under construction, and also through a filler 7 of tar or tar paper or other material which is permanently held between the ends of adjacent com leted sections, as usual in such constructions. rods with the caps applied to them extend in suitable positions lnto the section being formed, and the concrete is tamped around them. After allowing the material to set for a short time, the bulkhead is removed from the rods and the material of a succeeding section is tamped around the projecting ends of the rods.

Inasmuch as when the caps or end pieces are applied to the rods, the correct ini ial positions of the rods with their ends spaced from the ends of the caps is insured by reason of the contact of the ends of the rods with the pins which project into positions to engage them, no manipulation of the rods is required. Therefore, not alone are the proper positions of the parts to allow expansion or contraction of the rods or of the slabs in which they are contained, assured, but the second section of the roadbed may he proceeded with after only partial settingof the first section, thus effecting great economy in time of workmen. The pins by which the distance of introduction of the rods into the caps is determined, being of soft mate- The rial, offer no substantial resistance to the lengthening of the rods, and are readily sheared when under a rise in temperature the rods lengthen or are forced to move through expansion of slabs.

In practice it has been found that joints formed by the use of dowel rods of the form described, between concrete sections, are maintained for an indefinite period. The lubricant applied to the rods being encased in the concrete is not liable to deteriorate, and, therefore, as the rods can expand longitudinally, buckling liable to injure. the structure to which they are applied is impossible. The caps or end pieces being closed, no obstruction tending to confine the ends of the rods can enter. The caps, being firmly held in proper relation to the rods, furnish permanent chambers extending beyond the ends of: the rods, in which the rods may freely move when necessary to prevent their distortion.

I claim:

1. A dowel rod for the purpose specified. consisting of a metal bar, a cap of rigid material having a chamber therein receiving one end of the rod, and means for limiting the distance which'the rod is initially introduced into the cap.

2. A dowel rod for the purpose specified, consisting of a metal bar, a cap of rigid material having a chamber therein receiving one end of the rod, and a soft metal projection extending into the cap and by which the distance which the rod is introduced into the cap is limited.

3. A dowel rod for the purpose specified,.

consisting of a metal bar, a cap of rigid material having a chamber therein receiving one end of the rod, the exterior of the cap being provided with a projection adapted to be embedded in concrete or the like for holding the cup permanently in position in use, and a soft metal projection extending into the cap, and by which the distance which the rod is introduced into the cap islimited.

In testimony whereof I afiix my signature.

EDWARD A. MARYE. 

